无法从另一个类[Java]调用方法

Question

So I have three classes: Main, UserGroup, and User. In User I have three methods that are called in the UserGroup class and one which I am trying to call in the Main class. Using the methods in the User class I have created an ArrayList in UserGroup that has three different strings in each element (sorry if wrong term) and using the final method in the User class I am trying to change one of these strings.

The method I am trying to call is

public class User {
  String UserType;

  //some code removed

  public void setUserType(String x) {
      if ("user editor admin".contains(x)) {
          UserType = x;
      } 
      else {
        UserType = "editor";
      }
  }
}

I am trying to call this on a UserGroup called administrators that has an arraylist in it by putting this in main:

editors.setUserType("editor");

as this is how I called the other methods from UserGroup but I get an error of

error: cannot find symbol
        editors.setUserType("editor");
                      ^
symbol:   method setUserType(String)
location: variable editors of type UserGroup
1 error

EDIT (more of my main):

I create a UserGroup editors by

UserGroup editors = new UserGroup();

and add values to the ArrayList with

editors.addValues();

and then print the elements

editors.printData();

this all works as those methods are in the UserGroup class.

Answer 1

You maybe want to read into the topic overloading of methods in Java

It looks for the method with the header

public void setUserType()

but you only defined the method

public void setUserType(String x)

So you should call the method you created with something like:

editors.setUserType("Foobar")

Answer 2

It looks like editors is not actual a User. Maybe it is a List< User > in which case, it would be

editors.get(i).setUserType(x)

Answer 3

Does UserGroup contain a collection of User objects?

setUserType(...) is defined on User, but doesn't seem to be defined on UserGroup.

There are a couple of ways to do what you're trying to do.

1. Grab the list of User objects from your UserGroup, and call setUserType(...) on each one individually in main. Something like:

    List<User> users = editors.getUsers() //assuming UserGroup.getUsers() exists for(User user : users) user.setUserType("whatever"); 

2. Add a method to UserGroup called setUserType(...) that iterates through its collection of User objects and sets the types:

    public setUserType(String type) { for(User user : users) //assuming you have a collection of User objects user.setUserType(type); 

   }

If I'm describing this incorrectly, please add the complete implementation of UserGroup (or at least the part that shows how Users are contained), and we can provide more info.